750 Appendix L is driven by both the pins D D on opposite sides of it, and these pins are not fastened directly to the catch plate A, but to a separate cross-shaped plate E. The pins B B, holding plate E to the plate A, pass through slots in E, so that the latter is permitted to adjust itself to inequalities in the contour of the carrier c. lJjg. 734. P. i$j. Lathe Tools.—A simple and excellent roughing tool for a lathe is shewn in Fig. 735. A groove being fullered by the smith at a short distance from the tool point, the upper surface is ground to suit the tool angle in the direction shewn by the oblique arrow, while the relief angle is obtained by grinding, both'at front and side as shewn in the end view. (Seep. 976.) tr CHAPTER VI. P. 214. Gauges.—A very handy form of gauge is shewn in- Fig- 736. It combines in one tool the equivalent of plug gauge B, and ring gauge A. It is not quite so perfect in its application as, the cylindrical gauges, but will serve most ordinary purposes.